Product of Array Except Self

[cheatsheet1999]

Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]

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Example 1: Input: nums = [1,2,3,4] Output: [24,12,8,6]

Example 2: Input: nums = [-1,1,0,-3,3] Output: [0,0,9,0,0]

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It looks like we fliped the array, because we traverse from the back but get the result on the first index

1. Traverse from right to left and we got... [24, 12, 4, 1]
2. Traverse from the left to right, finally we got... [24, 12, 8, 6] leftMult was [1, 1, 2, 6]

var productExceptSelf = function(nums) {
    const res = [];
    let leftMult = 1;
    let rightMult = 1;
    for(let i = nums.length - 1; i >= 0; i--) {
        res[i] = rightMult;
        rightMult *= nums[i];
    }
    for(let i = 0; i < nums.length; i++) {
        res[i] *= leftMult;
        leftMult *= nums[i];
    }
    return res;
};